Hydraulically controlled gear driven drive axles are an efficient way of controlling the speed and direction of land vehicles, such as walk behind and ride-on lawnmowers, ATVs, and tractors. The axles are driven by a hydraulic motor, which receives pressurized hydraulic fluid from a hydraulic pump. The direction of rotation of the hydraulic motor and the rotational speed of the output shaft of the motor is a function of the operation of the fluid pump that is in communication with the hydraulic motor.
The operator of the vehicle controls the output from the hydraulic pump using controls, e.g. levers and the like. Return of the pump to a neutral position, a position in which the pump does not deliver pressurized fluid to the hydraulic motors, is desirable when the controls are not being operated by the operator of the vehicle. Known return-to-neutral mechanisms for hydraulic pumps are large and complicated.